In a plan released by his campaign, Walker also calls for requiring all unions to hold periodic votes so workers can decide whether they should continue to exist. If elected, he would also cancel President Barack Obama’s Labor Day order that federal contractors provide paid sick leave and work to end policies requiring some salaried workers in the private sector to receive overtime — saying in some cases they should get time off instead.

“Our plan will eliminate the big government unions entirely and put the American people back in charge of their government. Federal employees should work for the taxpayers — not the other way around,” Walker is to say in a town hall meeting at construction equipment maker Xtreme Manufacturing in Las Vegas.

Unions are braced for the speech and expected to react strongly against it.

“His whole theory of the case is fighting workers rather than helping working families,” Randi Weingarten, president of the American Federation of Teachers, said before Walker unveiled his plan.

The far-reaching proposals are in keeping with what brought the Republican governor to national prominence and allowed him to mount a campaign for the presidency.

His plan — all but impossible to pass, according to one observer — goes further than what he’s done in Wisconsin and would decimate private- and public-sector unions. That in turn would help Republicans at the ballot box because unions typically spend money to help Democrats.

Walker pitched his 2011 limits on collective bargaining as a way to solve the state’s budget woes by forcing government workers to pay more for their benefits. But he likely would not see equivalent savings at the federal level because federal workers are already barred from negotiating over wages and benefits. Instead, they bargain over work schedules, workplace safety and the like.

Walker’s move comes as his campaign is flagging. Viewed as a top-tier candidate for the first half of the year, Walker has seen his polling numbers plummet in recent weeks.

He has been retooling his message by saying he would “wreak havoc” in Washington, D.C. He will get another chance to test his message in the second debate for leading Republicans on Wednesday. Walker mostly faded into the background during the first debate last month.

In 2011, just weeks after he became governor, Walker proposed all but eliminating collective bargaining for most public workers in Wisconsin. That sparked massive protests and prompted Senate Democrats to leave the state for three weeks in an attempt to block the legislation.

Walker and Republican lawmakers overcame that opposition and put the measure now known as Act 10 into law. Their opponents tried to recall Walker from office, but he survived the effort, becoming the first governor in American history to win a recall election.

The campaign approach is different than ones he’s taken in the past.

Walker in 2010 campaigned on making public workers pay more for their benefits, but not on otherwise interfering with collective bargaining.

In his 2014 re-election bid, he repeatedly said efforts to pass a right-to-work law and curtail the state’s prevailing wage law would be a distraction — at one point pledging to do everything in his power to keep the right-to-work law from getting to his desk. This year, prodded by conservative lawmakers, he signed both pieces of legislation.

Now, as a presidential candidate, he plans to take on the unions head-on in his campaign.

Right-to-work laws prevent private-sector unions and businesses from signing labor agreements that require workers to pay union fees. With Walker’s approval, Wisconsin in March became the 25th state to have such a law.

Walker on Monday plans to call for passing a federal law that would put right-to-work policies in place in all 50 states. States would have the ability to override that policy.

Prevailing wage laws establish minimum wages for workers when they build highways, schools, or other publicly funded projects. Walker in July signed a state budget that included a provision — added by GOP lawmakers — that scaled back the prevailing wage law.

In many cases, those working on roads in Wisconsin will continue to receive their usual wages because of the federal Davis-Bacon law, which sets minimum salaries for projects that receive federal funding. Many road projects are funded jointly by the state and federal government.

Walker will call Monday for eliminating the Davis-Bacon law, which would allow taxpayers to save $12.7 billion over ten years, according to the Congressional Budget Office. Backers of the law say it ensures fair wages and repealing it would result in shoddy work that would end up costing taxpayers in the long run.

Walker also will call for transferring the duties of the National Labor Relations Board, which hears disputes between unions and employers, to the National Mediation Board and court system.

“The NLRB is broken beyond repair and should be eliminated,” Walker wrote.

Many of Walker’s ideas — such as dissolving the labor relations board and establishing a federal right-to-work law — would require changes to the National Labor Relations Act of 1935. Such changes have little chance of becoming law, said Joseph E. Slater, a labor professor at the University of Toledo in Ohio.

“The chance of that happening based on the historical evidence are basically, literally zero,” he said.

The last major change to the act was in 1959. When Democrats had large majorities in Congress in 2009 and 2010, they tried to make the law more favorable to unions but couldn’t get the measure through. Walker’s ideas would likely only pass if Republicans controlled the U.S. House and had a filibuster-proof majority in the Senate — and even then it would be difficult, said Slater.

“It’s really just red meat for the base,” Slater said. “None of that’s going to actually happen. I’m not certain you could get even 60 Republicans (in the Senate) to vote for that.”

The one area where Walker would have the greatest chance of success would be on preventing some employees from qualifying for overtime, Slater said. Which workers can get overtime is determined by federal regulations, so he wouldn’t need approval from Congress.

However, Walker also wants to allow employers to give workers compensatory time off instead overtime pay for any extra hours worked, and that change would require an act of Congress.

The tight limits Walker put on collective bargaining in Wisconsin in 2011 affected a broad swath of public workers, but largely left alone law enforcement officers and firefighters. Walker said he exempted them because the state could not risk having them go on strike; his critics noted that police and firefighter unions in Milwaukee were some of the rare labor groups to endorsed him.

Walker’s new labor plan would apply to all federal workers, including members of the Federal Bureau of Investigation, Border Patrol and other law enforcement agencies.

His 2011 changes left most public-sector unions with the ability to negotiate over wages but nothing else. Wages are capped at inflation. His new plan goes further, eliminating the ability of unions representing federal workers to negotiate on any issue.

Walker’s plan also proposes:

■ Ending the ability of unions to require government workers in some states to pay fees to unions.

■ Banning the federal government from withholding union fees from workers’ paychecks if they go toward political activities. Walker first floated that idea last week.

■ Barring caps that would prevent employees from being rewarded for exceptional work — a change in law that Walker says is needed because of the way some labor contracts are structured.

■ Establishing protections for union whistle-blowers.

Walker’s opponents railed against the proposals.

“It’s desperate and disgusting that Scott Walker would seek to revive his flailing campaign on the backs of middle-class workers and families,” said a statement from T.J. Helmstetter, a spokesman for the Democratic National Committee.

“It’s no surprise (Walker’s) now trying to boost his sagging poll numbers by promoting the same kinds of attacks on working people that vaulted him to national prominence while conveniently ignoring how his policies left Wisconsin in shambles,” said a statement from Scot Ross, executive director of the liberal group One Wisconsin Now.

Jason Stein of the Journal Sentinel staff contributed to this report from Madison.